How to properly add a Fragment to an Activity so that you can handle orientation changes

OC-AddingFragmentsActivity.java

private static final String TAG_MY_FRAGMENT = "myFragment";

private MyFragment mFragment;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    
    setContentView(R.layout.activity_adding_fragments);
    
    if (savedInstanceState == null) {
        // The Activity is NOT being re-created so we can instantiate a new Fragment
        // and add it to the Activity
        mFragment = new MyFragment();
        
        getSupportFragmentManager()
            .beginTransaction()
            // It's almost always a good idea to use .replace instead of .add so that
            // you never accidentally layer multiple Fragments on top of each other
            // unless of course that's your intention
            .replace(R.id.content_frame, mFragment, TAG_MY_FRAGMENT)
            .commit();
    } else {
        // The Activity IS being re-created so we don't need to instantiate the Fragment or add it,
        // but if we need a reference to it, we can use the tag we passed to .replace
        mFragment = (MyFragment) getSupportFragmentManager().findFragmentByTag(TAG_MY_FRAGMENT);
    }
}
...
public void myMethod() {
    // Later on in the code we can do something with the Fragment
    mFragment.doSomething();
}